If you're looking at their scores, then you're looking at their rudiments.
They largely use the same rudiments as the rest of us, though they tend to incorporate more of the Swiss Basel rudiments and style than North American marching bands. They use the Swiss style of notation - i.e. one hand on either side of a single stave line - as well.
I think the biggest difference isn't in the rudiments they use, but in the interpretation and application. Stylistically, they tend to a more legato approach than Drum Corps types. For instance, you'll find pipe band drummers tend to interpret their drags as closed buzzes rather than the strict two-stroke open drag you hear in "rudimental" drumming. That's not a hard, fast rule, but a tendency. They will also connect accents using buzzes and closed rolls more than Drum Corps players.
IMO - and this is only an opinion - the biggest differences are generated by the music they play. Pipe music, while used for marching (more like strolling much of the time - standard pipe band tempos are 100-108 BPM vs. the 120-132 of marching bands) is also traditionally dance music. Moreover, the predominance of 6/8 rhythms (or triplets depending on your perspective) such as the Strathspey gives a rounder, rolling feel. To accompany the whirling ornamentations of bag pipes a more lyrical and dance-like approach is necessary compared to the more militaristic and regimented style of the drum corps. You only need to watch them play, and take stock of their hand motions and technique to see the difference in approach.
That said, the best way to "get" the stuff (and I'm no expert, just a big fan) is to listen to it and watch as much of it as possible. Go see it live, and talk to the players.